JPS6351922A - Ceramic membrane structure and its manufacture - Google Patents

Abstract

PURPOSE:To prepare fluids of different formation at one port and the other port by providing a fluid inlet and an outlet at a blocking section of a port at one end of a ceramic honeycomb structure and also providing a ceramic film having continuous micropores around the inner circumference on the pore side. CONSTITUTION:Purge gas is introduced under pressure from a flow inlet 11a side of a case 11, and a first outlet 11b side is made to be a system open to atmosphere. By said arrangement, purge gas flows into an opening 21c from the lower end of each opening 21c provided on a ceramic film structure 20, and part of purge gas flowing out of a second outlet 11c of the case 11 through the upper end of the opening 21c, and gas fluid containing hydrogen gas of high concentration permeates each ceramic film 24 and an interstructure 21a passes through each fluid inlet and outlet pipes 23, and flows out of the first flow outlet 11b. The end opposing to the end with fluid inlet and outlet pipes 23 may be blocked.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ceramic membrane structure, particularly a ceramic membrane structure for gas separation by Knudsen diffusion or surface diffusion, and a liquid for filtering and separating minute solids and dissolved molecules in a liquid. -Relating to a ceramic structure for surface separation and its manufacturing method.

[Prior art]

As separation methods using membranes, microfiltration methods, ultrafiltration methods, gas separation methods, etc. are known, and various studies have been conducted in recent years. As an example, as shown in the publication Chemistry Devices, pages 61 to 65 (November 1985 issue: Kogyo Kenkyukai), a ceramic porous tube with micropores on its outer surface. There are examples of separating and removing moisture in the air and separating and concentrating alcohol using a structure supporting a silica gel thin film or an alumina gel thin film.

[Problem that the invention seeks to solve]

By the way, the above-mentioned publications do not provide any concrete means for utilizing such structures on an industrial scale, and a proposal for such concrete means is desired. The present invention focuses on a conventionally known ceramic honeycomb structure, and provides the same structure with a separation function by Knudsen diffusion of gas components and surface diffusion, and a filtration separation function of minute solids and dissolved molecules in liquid, thereby making it possible to industrially improve the structure. It is an object of the present invention to provide an advantageous ceramic membrane structure.

[Means for solving problems]

A first aspect of the present invention is to arrange a plurality of first pores that are open at one end and a plurality of second pores that are closed at the same end, which are partitioned by a porous partition wall having a large number of continuous pores, in parallel with each other. The structure is a ceramic honeycomb structure having fluid inlet and outlet holes in the closed portions of any of the pores, and has an average pore diameter of 100 Å to 5 Å on the inner periphery of each of the pores of each of the partition walls.
A ceramic membrane comprising a ceramic thin film having a large number of continuous fine pores of μm in size, the first pore and the second pore being at least partially separated by a common partition wall. in the structure.

Further, the second invention of the present invention is a method for manufacturing such a ceramic membrane structure, and the manufacturing method involves forming a large number of through holes partitioned by porous partition walls having a large number of continuous pores in parallel to each other. A ceramic honeycomb structure provided with a ceramic honeycomb structure is used as a basic structure, and a plurality of predetermined through holes in each of the through holes of the same structure (one end of which is closed at least on one end side and partitioned at least partially by a common partition wall) A large number of first pores are open on one side and a large number of second pores are closed on the same end side, and the average pore diameter is 100.
A slurry for forming a ceramic thin film having a large number of continuous fine pores of Å to 5 μm in size is infiltrated into the inside from the open end of any of the holes, and the ceramic thin film is formed on the inner wall of the hole. be.

In the present invention, the basic structure is a ceramic honeycomb structure obtained by extruding a mixture obtained by adding an organic binder and a plasticizer to fine powder of a ceramic raw material and kneading it through a die equipped with many slits, and then firing it. Alumina, silica, mullite, cordierite, etc. are used as ceramic raw materials. Such a ceramic honeycomb structure is provided with a large number of through holes in parallel with each other, separated by porous partition walls having a large number of continuous pores, and the cross-sectional shape of the through holes may be triangular, quadrilateral, other polygons, It has an appropriate shape such as a circle or an ellipse. Note that the average pore diameter of the pores of the porous partition wall is preferably 400 μm or less.

The ceramic membrane structure according to the present invention is formed by dividing each of the n through holes in the ceramic honeycomb structure into two types, ie, a first hole and a second hole. One end is open and the other end is open or closed. Further, at least one end of the second hole is closed, and the other end is closed or opened. The first hole and the second hole are at least partially separated by a common partition wall. In addition, such a ceramic membrane structure has a fluid inlet/outlet hole in the closed portion of any of the holes, and has a large number of continuous micropores on the inner periphery of each partition wall on either side of the hole. . Ceramic thin membranes have a large number of continuous micropores that diffuse and separate specific gas components in a mixed gas or filter and separate minute solids and dissolved molecules in a liquid, and are preferably made by hydrolyzing aluminum alcoholate or aluminum chelate. It is formed from the obtained alumina sol, and the average pore diameter of the micropores is 100 Å to 5.
It is preferable that the film thickness is 5 μm to 100 μm. The ceramic thin film-forming material is introduced into the ceramic honeycomb structure through the opening of any of the pores and attached to the inner wall thereof, and is subjected to appropriate treatment, such as immersion in an aqueous silicate solution, and then subjected to aquatic treatment in high-temperature steam. It is formed into a thin film. In addition, ceramic MH'A is pvp, c
It may be applied by the vp method, or a slurry containing fine powder may be applied by a known method.

[Action/effect of the invention]

In a ceramic membrane structure having such a configuration, a gas to be treated in which a plurality of gases are mixed, for example, H2Na gas, H2-C
O gas, H, S-H, gas, etc. are supplied from the open end of the first or second hole under pressure, and the fluid inlet/outlet of the closed part of either hole is made open to the atmosphere or sucked. For example, at least a portion of the gas to be treated tends to pass through the ceramic thin film and the partition wall. At this time, a specific gas, for example, H2 gas, passes through the ceramic thin film and the partition wall preferentially due to the difference in the permeation speed of each gas in the gas to be processed through the fine pores of the ceramic thin film. Therefore, two types of processing gases having greatly different gas compositions flow out from the first hole and the second hole. In addition, if a liquid produced by a microbial reaction containing microorganisms is treated, the permeation of microorganisms is regulated by a ceramic thin film, so the liquid produced after passing through the thin film and the partition becomes a clean liquid that does not contain microorganisms.

By the way, in the ceramic membrane structure having such a configuration, the ceramic honeycomb structure is used as the basic structure and the many partition walls of the same structure are provided with various separation functions, so the unit volume of the partition walls having the separation function is The effective area per hit is extremely high. Furthermore, since all of the partition walls are integrally connected, there is no need for means for integrating a large number of members constituting each partition wall, and the strength is extremely high. Therefore, such a ceramic membrane structure is industrially extremely advantageous as a gas separation structure or a liquid/surface filtration separation structure.

On the other hand, since such a ceramic membrane structure is manufactured by producing a ceramic honeycomb structure, closing a predetermined open end of a through hole of the structure, and forming a semi-ceramic thin film on the inner periphery of a predetermined partition wall, special care must be taken. It can be easily manufactured without using difficult means.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hydrogen gas separator surface employing a ceramic membrane structure according to a first embodiment of the present invention. The device includes a ceramic membrane structure 20 housed within a main body case 11, and is supported within the case 11 via a pair of upper and lower support members 12 and 13. Case 11 is inlet 1
1a and two outlets 11b and 11C, and the untreated gas passes through the inlet 11a under pressure (approximately 5 kg).
m/cot), and if the first outlet 11b side is open to the atmosphere, hydrogen gas is selectively diffused through the ceramic thin film by the pressure difference generated across the partition wall as described later. At the same time, the remaining gas with reduced hydrogen gas concentration flows out from the second outlet 11c.

Thus, the ceramic membrane structure 20 is shown in FIGS.
As shown in the figure, the basic structure 21 is a ceramic honeycomb structure having a large number of through holes separated by porous partition walls in parallel. ) have a rectangular cross section and extend in parallel to each other in the longitudinal direction of the structure 21. This structure 21 is made by extruding a mixture obtained by kneading fine powder of a ceramic raw material such as alumina, silica, mullite, cordierite, etc. with an organic binder and a desensitizer under the same conditions as for forming a normal ceramic porous material. The large number of partition walls 21a that partition each through hole are porous partition walls having a large number of continuous pores. FIG. 4 shows a highly enlarged local cross section of the partition wall 21a and a ceramic thin film 24, which will be described later.
The average pore diameter of 1b is preferably 400 μm or less.

If the average pore diameter is less than this, it is possible to prevent the occurrence of cranks, pinholes, etc. in the heavy membrane for forming a ceramic thin film, and to form a uniform film thickness.

Note that the thickness of the partition wall 21a is arbitrary, but from the viewpoint of strength and processing, it is preferably about 111 mm thick.

In the ceramic membrane structure 20 of this embodiment, both ends of each through-hole in the structure 21 are closed in a staggered manner, and each through-hole is divided into a large number of both-end open holes 21C and both-end closed holes 21d. are doing. These holes 21C and 21d correspond to the first and second holes in the present invention, respectively, and the closing member 211 closes both ends of the closing hole 21d.
．． The partition wall 22b is made of the same material as the partition wall 21a and has a glaze applied to the outside thereof, and is airtightly sealed. A fluid inlet/output pipe 23 made of the same material is implanted in the closing member 22a. Open hole 21c and closed hole 21d adjacent to each other
are partitioned on one side by a common partition wall 21a. Further, a ceramic thin film 24 is formed on the inner periphery of the partition wall 21a that constitutes each opening hole 21C.

The ceramic thin film 24 has a large number of continuous fine pores 24a that diffuse and separate hydrogen gas by Knudsen diffusion, and the average diameter of the fine pores is 100 Å to 1000 Å.
When used in microfiltration and ultrafiltration, the average pore diameter may be up to 5 μm, depending on the size of the substance to be treated.

The reason why the average pore diameter of the ceramic thin film 24 is set to 5 μm or less is because if it exceeds 5 μm, the resistance for fluid to pass through the ceramic 3 membrane 24 becomes small, so the partition wall 21 becomes unnecessary and a single layer structure may be preferable. It is from. Further, the thickness of the ceramic thin film 24 is 5 μm to 100 μm.
By making the thin film with a separation function thinner, the resistance to fluid passage is lowered, making it easier for fluid to pass through. In this example, the average pore diameter of the micropores was 100A, considering the diffusion permeation rate of hydrogen in purge gas for hydrogen sulfide decomposition reaction, ammonia synthesis, methanol synthesis, etc.
The film thickness is adjusted to 10 μm. The ceramic thin film 24 is made using an alumina sol obtained by hydrolyzing an aluminum alcoholate such as aluminum isopropoxide or aluminum-2-butyrate, or an aluminum chelate such as aluminum tris (ethyl acetoacetate) or ethyl acetoacetate aluminum diisopropylate. Structure 2 is formed in the same alumina sol.
1 is immersed and introduced into each opening hole 21C, and the partition wall 2
It is supported on the inner periphery of the same opening hole 21C (1111) of 1a. Thereafter, it is treated with a sodium silicate aqueous solution and further treated with high-temperature water vapor to form a thin film 24 of water. 5 g of aluminum isopropoxide per 100 g was added to water maintained at 80 to 90°C to hydrolyze the aluminum isopropoxide. To this, Q, 5 mj2 of concentrated nitric acid was added,
The mixture was kept at ~90°C for 24 hours and peptized to obtain an alumina sol. The structure 21 was immersed in this alumina sol for 5 minutes, dried at 0°C, and fired at SOO°C for 3 hours.

In the hydrogen gas separation device that employs the ceramic membrane structure 20 having such a configuration, the purge gas described above is supplied under pressure at a predetermined flow rate from the inlet 112 side of the case 11, and the first outlet 11b side is connected to the atmosphere. It should be an open system. As a result, the supplied purge gas is transferred to the ceramic membrane structure 20.
A gas fluid containing high concentration hydrogen gas flows into each opening hole 21c from the lower end of each opening hole 21C, and a part of it flows out from the second outlet port 11C of the case 11 through the upper end of the opening hole 21C. Ceramic thin film 24 and partition wall 21
a and passes through each fluid input/output pipe 23 to the first outlet 1
It flows out from 1b. FIG. 4 shows a horizontal view when the purge gas passes through the ceramic thin film 24 and the partition wall 21a. The particles preferentially move inside the micropores 24a toward the partition wall 21a, reach the micropores 21b of the partition wall 21a, and flow into the closed holes 21d. As a result, purge gas with a low hydrogen gas concentration flows out from the second outlet 11c, and purge gas with a high hydrogen gas concentration flows out from the first outlet 11b.

By the way, the ceramic membrane structure 20 of this embodiment has a conventionally known ceramic honeycomb structure 21 as its basic structure, and the numerous partition walls 21a of the structure 21 have a gas diffusion separation function. be. Therefore, the effective area per unit volume of the structure 21 of the partition wall 21a having the diffusion bone m function is large, and there is no need for a means to integrate a large number of members constituting each partition wall 21a, and the strength is extremely high ( , which is extremely advantageous industrially.

Furthermore, in the ceramic membrane structure 20 of this example,
Extrusion molding is performed under normal manufacturing conditions for ceramic honeycomb structures, and predetermined openings at both ends of each through hole in the structure 21 are closed using the same material as the clay for extrusion, and fluid inlet and outlet holes 23 are implanted. The structure 21 is fabricated by setting and then firing. Alternatively, the structure 21 may be produced by extrusion molding and firing, and then predetermined openings at both ends of the structure 21 may be closed. Therefore, according to this manufacturing method, the ceramic membrane structure 20 can be easily manufactured since no particularly difficult or complicated means are used.

5 and 6 show a portion of a ceramic ljitl structure 30 according to a second embodiment of the invention. In the ceramic membrane structure 30 as well, the basic structure 31 is a ceramic honeycomb structure similar to the basic structure 21 of the first embodiment, and there are differences from the ceramic membrane structure 20 of the first embodiment. The points are below. That is, in the ceramic membrane structure 30, only one end of the second hole 31d corresponding to the closing hole 21d of the ceramic membrane structure 20 of the first embodiment is closed with the closing member 32a; In the first hole 31c corresponding to the opening hole 21C, one end is open and the other end is closed to the closing member 32.
It is closed at b. In addition, in this ceramic membrane structure 30, the partition wall 31 constituting the first hole 31c
Sera E -/riilj on the inner circumference of a! 34, and a second
A fluid inlet/output pipe 33 is installed in a closing member 32a that closes one end of the second hole 31d, and supplies purge gas from the other end of the second hole 31d.
C, and the first hole 31c is kept under vacuum. As a result, hydrogen gas in the purge gas selectively permeates through the partition wall 31a and the ceramic thin film 34 and flows out from the outlet 11c through the first hole 31C, and the purge gas with reduced hydrogen gas concentration passes through the second hole 31C. It is obtained from the other end side of the hole 31d.

Moreover, the ceramic thin film 34 inside the first hole 31c
Similar effects can be expected even if the hole is located inside the second hole 31d. Furthermore, the purge gas may be filled into the first hole 31c using the second outlet 11c, and the hydrogen gas selectively diffused through the ceramic thin film 34 and the partition wall 31a may be recovered from the second hole 31d. good.

In the ceramic membrane structure 20 of the first embodiment described above, the fluid inlet/output pipe 23 is installed only in the closing member 22a at one end of the closing hole 21d.
A similar fluid inlet/output pipe may be installed in the closing member 22b at the other end of d, so that the purge gas flowing through the opening hole 21C flows out from both ends of the closing hole 21d which is open to the atmosphere.

In addition, the above-mentioned 1. In the ceramic membrane structure 20.30 of the second embodiment, each of the closing members 22a, 22b, 3
2a and 32b have the function of airtightly closing, but the partition walls 21a and 31a or the partition wall 2 serve as each closing member.
1a, 31a and the ceramic thin film 24, 34 may be made of an integral material to provide air permeability. In these cases, the gas in the hole can be directly sucked through each closing member, and the use of fluid inlet/output pipes 23 and 33 can be omitted, and the ability of component Mi in the closing member and the fluid inlet/outlet can also be expected. can.

Furthermore, the ceramic membrane structure 30 of the second embodiment described above
Although the ceramic thin film 34 is formed on the inner periphery of each partition 31a on the first hole 31C side, the same thin film 34 may be formed on the inner periphery of each partition 31a on the second hole 31d side.

Furthermore, in the above embodiment, a ceramic membrane structure 20.3 for diffusing and separating hydrogen gas in the purge gas is used.
By appropriately setting the average pore diameter of the ceramic thin films 24 and 34 in each of these structures 20 and 30, specific gases in various mixed gases can be controlled by Knudsen diffusion, surface diffusion, etc. It can be used as a ceramic membrane structure for diffusion separation to separate in water, or as a ceramic membrane structure for liquid/surface filtration separation to filter microorganisms, proteins, and other minute solids in various solutions.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a hydrogen gas separation device employing a ceramic membrane structure according to a first embodiment of the present invention, FIG. 2 is an enlarged perspective view of the same membrane structure, and FIG. Fig. 4 is an ultra-wide sectional view of the partition wall in the same structure;
5 is a perspective view corresponding to FIG. 2 of a ceramic membrane structure according to a second embodiment of the present invention, and FIG. 6 is a perspective view of a ceramic membrane structure according to a second embodiment of the present invention.
FIG. 3 is a sectional view corresponding to the figure. Explanation of symbols 20.30...Ceramic membrane structure, 21.31...
・Foundation structure, 21a, 31a... partition wall, 21b...
- Pore, 21c, 31c...first pore, 21d, 31
d...Second hole, 24.34...Ceramic thin film,
24a... Micropore.

Claims (9)

[Claims] (1) Ceramic honeycomb structure comprising a large number of first pores that are open at one end and a large number of second pores that are closed at the same end and that are partitioned by a porous partition wall having a large number of continuous pores in parallel with each other. The structure has a fluid inlet/outlet hole in the closed part of any of the holes, and has a large number of continuous fine pores with an average pore diameter of 100 Å to 5 μm on the inner periphery of each of the partition walls on the hole side. A ceramic membrane structure comprising a ceramic thin film, wherein the first hole and the second hole are at least partially separated by a common partition wall. (2) the other end side of the first hole is open, and
The ceramic membrane structure according to claim 1, wherein the other end of the second hole is closed. (3) the other end side of the first hole is closed;
The ceramic membrane structure according to claim 1, wherein the other end of the second hole is open. (4) The thickness of the ceramic thin film is 5 μm to 100 μm
A ceramic membrane structure according to claim 1, 2 or 3. (5) The ceramic membrane structure according to claim 1, 2, 3, or 4, wherein the average pore diameter of the pores of the partition wall is 400 μm or less. (6) Claim 1, wherein the closing portion is formed of the same porous material as the partition wall or the ceramic thin film.
The ceramic membrane structure according to item 2, item 3, item 4, or item 5. (7) Claims 1, 2, 3, and 4, wherein the closing portion is formed of a non-porous airtight material, and a fluid inlet/output pipe is implanted in the closing portion. The ceramic membrane structure according to item 1 or 5. (8) A ceramic honeycomb structure having a large number of through holes in parallel with each other separated by porous partition walls having a large number of continuous pores is used as a basic structure, and a predetermined area in each of the through holes of the structure is provided. At least one end side of each of the through holes is closed, and a large number of first holes with one end side open and a large number of second holes with the same end side closed are partitioned at least partially by a common partition wall. A slurry for forming a ceramic thin film having a large number of continuous fine pores with an average pore diameter of 100 Å to 5 μm is introduced into the inside from the open end of any of the pores, and the ceramic thin film is formed on the inner wall of the pore. A method for manufacturing a ceramic membrane structure characterized by: (9) The method for producing a ceramic membrane structure according to claim 8, wherein the slurry is an alumina sol obtained by hydrolyzing aluminum alcoholate or aluminum chelate.